1. Field of the Invention
The invention relates to a collapsible fire fighting bucket adapted to be suspended from an aircraft, especially from a helicopter, and to be filled from an open body of water, eg. from a lake or river.
2. Prior Art
A collapsible fire fighting bucket adapted to be suspended from a helicopter and to be filled by immersion into a lake is known from U.S. Pat. No. 3,661,211 to Powers. This bucket is formed of a collapsible external frame which supports the flexible side walls. The frame includes a rigid upper peripheral frame member connected to a rigid circular bottom member by means of four rigid, normally upright, but collapsible braces. The water is released from the bucket by opening two doors in the bottom by means of a ram operated by pressurized fluid. Slots, closable by zippers, are provided at a certain height in the flexible side wall for limiting the capacity of the bucket and thereby adapting it to the lifting capabilities of the aircraft. This known bucket is rather bulky in its collapsed state, and the rigid, flat bottom with its water release mechanism makes it fairly heavy and expensive to manufacture.
U.S. Pat. No. 3,572,441 to Nodegi describes a liquid discharge tank for fire fighting in the shape of a flexible bag, closed at the top and having a snout-like extension at its bottom. The extension can be pulled into the bag by means of a rope attached to its lower end. The rope is guided through the central opening of a cylinder, which closes the upper end of the bag and has a hanging bar adapted to be connected to the underside of a helicopter. A combined solenoid and hydraulically operated locking mechanism locks a stopper on the rope inside the cylinder to keep the extension in its withdrawn position when the bag is full. When the mechanism is released, the extension is forced out of the bag under the pressure of the liquid, thereby releasing the liquid onto the fire. When the bag is empty, the rope and with it the extension is pulled up again.
The discharge port of the extension must be positioned above the liquid level inside the bag in order to prevent leakage. Because of this, the extension has a considerable length and can get twisted when the rope is released, so that the liquid cannot be dumped from the bag. Twisting can also make it impossible to withdraw the extension into the bag. This bag must be filled through the extension and cannot be filled by dumping it into a lake, which limits its application because a filling station is required. Valuable time can be lost by this way of operation, and the fighting of forest fires, especially in remote areas, is not practical with this device.